Πέμπτη, 24 Απριλίου 2008

Κυριακή, 6 Απριλίου 2008

All that is iron-ink is not always iron-gall!


Στο προηγούμενο τευχος του Journal of Raman Spectroscopy (April 2008), οι Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo παρουσιάζουν μια εργασία με τίτλο: "All that is iron-ink is not always iron-gall!".

In the previous Issue of Journal of Raman Spectroscopy (April 2008), Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo present a paper titled: "All that is iron-ink is not always iron-gall!".

Περίληψη/Abstract: A number of different inks were used, with the type and precise composition depending on geographical area and historical period. China, iron-gall and logwood were the most widespread, although a number of other graphic media were also used at particular times and places. Because of a problem encountered while planning the restoration of a manuscript apparently written with different media, we have carried out a systematic characterization of the inks involved. The manuscript (Francesco Maria da Ponticelli, Nova Rhetorica, 18th century) showed alternately, sometimes in the same page, dark-black well-defined inks and reddish-brown smudged ones. The latter ones were very difficult to be read and historians identified it as an iron-gall. Our first investigations of the document revealed that the ink had variable composition, but it always showed some typical features of logwood ink. To obtain a better understanding, we prepared, following ancient recipes, logwood inks with the addition of various metallic (Fe, Cr and Cu) salts or amorphous carbon. Iron-gall ink was also used for comparison and in order to obtain an unambiguous and full characterization of the most widespread inks used in manuscripts. Raman and infrared spectroscopies allowed us to identify the characteristic vibrational features of each prepared medium. These techniques, together with X-ray fluorescence (XRF) and multispectral investigations of the original document led us to hypothesize that iron salts were periodically added to the original logwood ink. These sequences of ink quality can be ascribed to a shortage of ink during the writing of the manuscript. A small amount of iron salt immediately darkens the logwood extract, allowing its prolonged use. The presence of iron complexes produces a reddish-brown coloration and causes ink migration in the paper. Combining all the information, we were able to suggest an appropriate restoration treatment and to choose infrared illumination to maximize the readability of the text.

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